I just opened up a couple bottles of a brown ale I just brewed, and there is much less carbonation then I had hoped. The beer was in the primary for a week, secondary for 3 weeks, then primed and bottled for two weeks before tasting. Is there anything I can do at this point? In the future, what should I be looking out for to prevent this?

I have had the last five batches barely carbonate. I haven't changed anything in my brewing technique for the last four years and I make about 30 kits a year. Temperature, timing, beer type and measurements haven't changed. Need help as the store here I buy from is baffled!
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user3024Jan 15 '13 at 1:19

(There could be other problems, but this is the most likely one. Other potential causes are too little head space between the beer and cap, using screw top bottles that can allow air to escape, and a few other random issues, but the priming sugar is likely the culprit.)

I'll just add to the answer here; temperature can be an issue too. You really want to store the bottles in a place as warm as (if not a little warmer) than your primary ferment. The cooler they are the longer it takes to carb up.
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brewchezJul 15 '10 at 11:10

1

I ended up waiting a full month (for a total of six weeks conditioning) before the next taste. That was the key. The extra time also really helped with the flavor as well.
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JasonOct 1 '10 at 13:02

I'm adding this as another answer because I agree with all of Markskar's answer and the first part of Jordan's (though I admire his dedication re: the 2nd part of his answer).

I'd just wait. Make sure to age them in an area that doesn't get too cold or too hot-- like 60 - 70º. Depending on your ABV and the amount of priming sugar you used, carbonation time varies. I made a barleywine last year and the 10% ABV killed off the majority of the yeast in there. It took 3 months to fully carbonate, but now it's pouring a head you can almost stand a fork up in. So be patient and see what happens. So if you have high ABV, that's a factor for sure. It was also quite cold in my garage for the first month, and I'm suspecting that summer temps encouraged the remaining yeast to come out of hibernation.

I've definitely seen carbonation increase substantially in the third week. Beyond that, it drops off, but doesn't stop. I tend to bottle in various sizes (12oz, 500ml, 22oz, 1L). I've heard others say that the bigger bottles tend to get more carbonated than the smaller ones, due to an approximately equal amount of head space for a larger volume of beer.

After a week, try a couple of bottles of the same size from different sides of the batch. If you get different carbonation levels, it may be that you didn't have your priming sugar adequately mixed through your batch. To mitigate this:

Don't make your priming sugar solution too thick

Put it in the bottling bucket first

Rack your beer on top of the solution to mix well

Give it a gentle but thorough stir with a sanitized spoon

Give it another stir halfway through the bottling process

Try to maintain consistent head space in filling

Fixes

I've never tried this, but you might try opening the bottles, throwing in a couple of Munton's Carb Tabs (one to replace the carbonation you just let out, one to add some extra) into each 12 oz bottle. They get mixed reviews, though, so I'd be more likely to try one Cooper's Carbonation Drop per 22 oz bottle. Might get a gusher. Might hit it just right. If I were to do this, I would condition the bottles in a container that's going to be able to mitigate the damage of a bottle bomb.

Time. Leave them alone and come back to them later. You might see better results as time goes by.

Give it time and make sure you're storing your beer at a reasonable temperature while it conditions. I generally cellar mine upon bottling (~60-65 degrees year-round) and have only once had an issue with low carbonation, which did correct over time.

I had this same issue back a few months ago. The problem was that there were not enough yeast still alive to consume my priming sugar. I ended up dumping out every bottle very carefully into a bucket, boiled some water and added 2 cups of priming sugar to it, siphoned all of it back into a carboy, added more yeast, and let it ferment out. Then I rebottled and everything carbonated fine and the beer turned out just fine. This probably is not the proper way to handle the situation, but it worked.